Pneumatic peening and marking tool



'July 12, 1960 M. w. KIBBE, JR

PNEUMATIC PEENING AND MARKING TOOL Filed Nov 28, 1958 INVENTOR. M170 W K/bba, Jr

u/Mwdl, Mum

Un te swea k 2,944,521 PNEUMATIC PEENING AND MARKING TOOL' Milo-W. Kibbe, In, New Haven, Conn., assignor to Plane Parts, Inc., New Haven, Conn., a corporation of Connecticut Filed Nov. 28, 1958, Ser'. No. 777,053 7 2 Claims. (Cl. 121--'17) This invention relates to a pneumatic :peening' and marking tool, and more particularly to a pneumatic peening and marking tool in which there is provided a self-oscillating piston which acts as the vibrating element.

This application is a continuation-in-part of my application Serial No. 648,663, filed March 26, 1957', now

abandoned.

Self-oscillating pistons are not in themselves new.

- However, heretofore they have principally been used in hammer type devices in which the force generated by each'stroke is the important thing, and the'speed with which'the strokes are delivered is secondary;

' On the other hand, in pneumatic peeningand marking:

tools heretofore available, in which the vibrating ele'-- in driver bushing cap end thereof which projects from the driver bushing cap;

and fitted into the recess is an exchangeable peening or marking tool 17.

The collar 19 is mounted 'on the driver within the unthreaded part of the enlarged end 12a of the bore*12.' A return spring is positioned between the collar 19 and the inner end of the driver bushing cap 13, which. spring tends to urge the collar 19 away from the driver bushing cap.

" also has a further air outlet 18 therein, which outlet opens outlof the end-of the cylinder bore 21 away from The enlarged handle portion 11 of the body 10 has a cylinder bore 21 therein, which cylinder bore joins the bore 12. The cylinder bore 21 hasan enlarged outer end 21a.' The wall of the enlarged handle portion 11 has -a threaded air inlet 22 therein which opens into theenlarged'outer end 21a. The wall of the enlarged handle portion ll also has two diametrically opposed air .outlets 23 therein which open. out of the cylinder bore 21 adjacent said air inlet 22. The wall of the body 10 the inlet 22., This air outlet is always at least par,- tially open. The length of the driver from the collar to the" inner end thereof plus the thickness of the collar] and the spring '20 whenTit is'compressed being greater ment mus be rapidly oscillated to produce a reasonably continuous marking, the vibrating element. isr -generally oscillated by means of complicated valve arrangements or special air supply arrangements which'notonly are expensive to own 'butare noteasily adjusted and kept adjusted. In the case of those tools-which require a than the distance'fron'i the inner. end'of the driver b.ll Sh- 'ing: cap 137tofthe edge of the outlet 18 closest thereto.

A differential piston 24 "is slidab'ly positionedv ;in-the" cylinder bore 21. .It has alarger diameter part 25 in the enlarged outer end 21a'of. the cylinder bore and a smallerdiameter part-26 in-the cylinder-bore 21. The; end" of the smaller'diameter part 26 bears against the end of thedriver 15 'which projects into the cylinder bore 21. The difierential piston 24 has 'a ,largerend.

area;27 on the :end'of thelarger diameter part 25' and a er. diameter part 26.

provide apneumatic peening and marking tool in'whichthe vibrating element is automatically and rapidly reversed by the construction of the vibrating element and the tool itself, the parts of the tool being simple to make and assemble-and the tool itself being easy to maintain.

Other andfur ther objects of the present invention will 1 be apparent from the following description and the appended claims taken together with the accompanying drawing, in which: a j D Fig. 1 is a sectional elevation ofthe tool according to the invention; and

Fig. 2 is a cross sectional elevation view takenjalong line 2-,-2 of Fig. -1. 1

As seen in Fig. l, the pneumatic peening and marking tool according to the invention consists of a body 10 with an enlarged handle portion 11 on one end thereof. Extending into the body 10 from one end thereof is a bore 12 which has an enlarged outer end 12a. The outer portion of the enlarged outer end is internally threaded. A driver bushing cap 13 is threaded into the threaded portion of the enlarged outer end 12a of the bore 12. The driver bushing cap 13 also has a bore therethrough. A- nylon driver bushing 14 is inserted into the end of the driver bushing cap and surrounds the bore in the driver bushing cap. A driver 15 is slidably positioned in the bore 12- and extends through, the bore smaller area 28 between the; larger diameter part 25 and the smaller diameter part'26, which area is, the difierence between the cross sectional area of the larger diameter part 25 and the cross sectional area of the smallfThe diiferential piston 24 has an axial bore 29 therein which opens outof the piston at the larger 'end area.

27. The piston also has four piston bore outlets 30, extending at right angles to each other, which open out of the axial bore 29 of the piston into a circumferential groove 30a inthe smaller diameterpart 26.}; T:

An end cap 32 is threaded into the threaded end 31 of -the. enlarged outer end 21a of the cylinder bore 21. In the position of the tool shown in Fig. l, it is ready to start'a'cycle. The piston boreoutlets 30 openo ut of the smaller diameter part 26 into the groove 30a in thepiston' andthrough air outlets 23. Thelength of the-differential piston '24 is such that the larger diameter part 25 is positioned in'relation tothe air inlet 22 such thatjair admitted through air inlet 22 will apply iair pressure against the smaller area, 28. ,The end of' the" smaller diameter part 26 is against the end of the sliding rod 15; I

, When the air under pressure from a conventional source of steady air pressure is admitted through inlet,

22, it appliespressure to the smaller area 28. Since the space within the enlarged outer end 21a of the cylinder bore 21 is open to the atmosphere through the axial bore 29 and the outlet 23, the pressure on the smaller area 28 will be larger than the pressure on the larger end area 27, and the piston 24 will beurgedtoward the end cap 32. When the piston 24 has moved far enough so that the piston bore outlets 30 are open to the air inlet 22, however, the space within'the enlarged outer end' 21a of the eylinder bore21 will be op'en to the Patented July 12, 1960 13 and through the nylon' driver bushing 14. The driver 15 has a recess 16 in the 3 air pressure through the axial piston bore 2Q. The air pressure will then be applied to both the larger end area 27 and the smaller area 28, and the difference in total pressure will drive the-piston 24 toward the driver The momentum built up during the; movement under the effect of the differential air pressure will cause. the piston 24 to strike the slidingrod' 15, which in turn:

will transmit the impact to the exchangeable tool 17.

At this point the piston bore oulets 30 and thegroove By reason of the provision of the groove 30a. in thepiston, and the four radially directed outlets from the piston bore which open into the groove, the air is quickly and easily released from behind the larger end area of the piston. 'Moreover, since there are four outlets 30, and there are two diametrically opposed outlets 23 in the body 10, if any one of the outlets 30 is aligned with either of the outlets 23, one of the otheroutlets 3% will be aligned with the other outlet 23, thus further facilitating the quick release of the air driving the piston on its driving stroke.

In addition to the structure which provides-for a quick release of the air behind the piston, there is provided the air outlet 18 which always vents thespace atthe inner end of the cylinder bore 21. There can thus never be an air cushion to slow down the stroke of the piston. The only reversing force is the return spring 20, which will act much more quickly than an air cushion and spring combined. 1

This structure thus provides for quick release of the air pressure driving the piston on its driving-stroke and for quick reversal of the piston. This promotes rapid operation of the device whichresults in the production ofa substantially continuous line by the tool 17.

It is thought that the invention and its advantages will be understood from the foregoing descriptionand it is apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing its material advantages, the form hereinbefore described and illustrated in the drawings being merely a preferred embodiment thereof.

I claim: a 1

1. In a pneumatic peening'and marking tool, the combination of a tool body having an enlarged handle portion onone end thereof, said body having a bore in'the other end thereof with an enlarged outer end, a driver bushing cap inthe outer portion of said enlarged outer end, a driverhaving a collar thereon insaidbore with said collar in said enlargement, said-driver having a tool holding recess in the'end thereof projecting from the body, a spring insaid enlargement between said driver bushing cap and said collar, said spring urging said drivcr-away from the end of said body from which said The piston will thenbe ready to repeat driver projects, the enlarged handle portion of said body having a cylinder bore therein joining the bore in said body, said handle portion having therein at least one threaded air inlet to said cylinder bore and two diametrically opposed air outlets from the portion of said cylinder bore adjacent to said air inlet, said air inlet and air outlets being spaced from each other along the length of said handle portion, and a further air outlet from the end of said cylinder bore away from said air inlet,. a differential piston in said cylinder bore having a larger diameter and a smaller diameter part, said piston having an axial bore therein opening out of the end of said piston at the larger diameter part, said smaller diameter part havingla circumferential groove therein and four outlets opening into said groove from said axial piston bore and spaced at equal angles around said piston, and a closure cap closing the end of said piston bore, the length of the said driver from said collar to the end thereof adjacent said piston, plus the thicknessof said collar and said spring when it is compressed is greater than the length of said body from the inner end of said driver bushing cap to said further air outlet, whereby said further air outlet always vents the inner end of said cylinder bore.

2. A motor for a pneumatic peening and marking tool, comprising a tool body having an enlarged handle portion on one end thereof, said body having a bore in the other end thereof with an enlarged outer end, a driver bushing cap-in the outer portion of said enlarged outer end, a spring in said enlargement, the enlarged handle portion of said body having a cylinder bore therein joining the bore in said body, said handle portion having therein at least one threaded air inletto said cylinder boreand. two diametrically opposed air outlets from theportion of. said cylinder bore adjacent to saidair inlet, said air inlet and air outlets being spaced from each other along the length of said handle portion, and afurther air outlet from the end of said cylinder bore away from said air inlet, a differential pistonin said cylinder bore having a larger. diameter and a smaller diameter part, said piston having an axial bore therein opening out of the end of said piston at the larger diameter part, said smaller diameter part having a circumferential groove therein and four outlets opening into said groove from said axial piston bore and spaced at equal'angles around said piston, and a closure cap closing the end of said piston bore, whereby when a driver having a tool holding recess therein and having a collar thereonis placed in said tool body, it will project from said body and said spring will fit between. said collar and the bushing'cap and urge said driver away from the end: of said body in which said driver bushing is pushed;

References Cited in the'file ofthis patent UNITED STATES PATENTS 1,428,630 Hammond Sept. 12, 1922 1,872,403 Cannon Aug. 16, 19.32 2,346,474 DeLaTarre Apr. 11,1944 2,392,560- Vitoux Ian. 8,1946 2,585,975 Terry Feb..l9,p1952 

